Warding off distractions in prayer

ALLAH has specified the qualities of successful believers who will inherit the Highest Paradise, Jannah Al-Firdous, in the Qur'an. One of them is Khushoo'.
"Successful indeed are the believers. Those who offer their Salat (prayers) with all solemnity and full submissiveness (Khushoo')." (Qur'an, 23:1,2)

The term 'Salah', is derived from the root word 'Silh' which means connection i.e. the connection between us and Allah.

The Messenger of Allah (peace be upon him) said, "When anyone of you stands for prayer, he is conversing with his Rabb, so let him pay attention to how he speaks to Him." (Al-Hakim, Al Mustadrak, 1/236; Sahih Al-Jami' no.1538)

Consider three types of houses:
* A king's house: filled with treasures, but with guards on all four corners.
* A haunted house, which is very dark.
* A common man's house: filled with his savings and treasure.

Now, if a thief comes to steal from one of the three houses which one will he choose? Obviously, the house of the common man because it has something of value and is not guarded.

This is the example of our hearts. The first is similar to the hearts of prophets i.e. well-guarded, the second is the heart of those who don't believe in Allah as He deserves, and the third is similar to the heart of common believer like you and me. This is why Shaitan attacks our hearts and that's why we sometimes find ourselves praying with Khushoo' and sometimes not.

Solution

The Prophet (peace be upon him) has asked us to seek refuge in Allah from Satan.
Abul Aas once asked, "O Messenger of Allah (peace be upon him), the Shaitan interrupts me when I pray, and I get confused in my recitation." The Prophet (peace be upon him) said, "That is Shaitan (whose name) is Khanzab. If you sense his presence, seek refuge with Allah from him (i.e. say A'oodhubillaahi min-ash-Shaitaan-ir-rajeem), and spit (dry spitting) towards your left three times." Abul Aas said: "I did that and Allah took him away from me." (Sahih Muslim, no. 2203)

Apart from this, try to prepare for Salah in advance. Have Wudhu before the Adhan. Answer the Adhan and say the Du'a the Prophet (peace be upon him) taught us to say after hearing the Adhan. Go to the mosque in advance. Avoid unnecessary talk before prayer, instead try to be busy with Tasbeeh and Istighfar. When you're praying at home, recite different Surahs and not just the smallest ones you keep repeating all the time. And most importantly think about the greatness of Who you are going to stand in front of in prayer.